Marking element and method of making same



Sept. 2, 1969 K. F. BEAL MARKING ELEMENT AND METHOD OF MAKING SAME Fileslfiept. e. lss'z United States Patent 3,464,775 MARKING ELEMENT AND METHOD OF MAKING SAME Keith F. Bea], Chicago Heights, Ill., assignor to Sanford Research Company, Bellwood, 111.,

a corporation of Illinois Filed Sept. 6, 1967, Ser. No. 681,303 Int. Cl. B43k /18; 343m 11/06 U.S. Cl. 401-199 7 Claims ABSTRACT OF THE DISCLOSURE There is disclosed a marking device including a marking element comprising a bundle of thermoplastic fibers. The outermost fibers are thermally joined together to provide an imperforate self-sustaining shell and an end of the element is heat formed to provide a reduced outlet opening for an enlarged relatively rigid self-supporting end portion.

The present invention relates to a novel marking device, and more specifically to a novel marking element and method of producing the same.

A variety of marking devices utilizing felt tip or similar marking elements have been suggested and successfully used for applying a marking fluid on all types of surfaces ranging from porous cardboard and paper to relatively non-porous material such as metal or glass. In general, such marking devices have been used for marking or writing with relatively broad lines. Attempts have been made to provide such marking elements with relatively sharp points, but problems have been encountered as a result of the tendency for the relatively sharp points of a felt-type material to wear away or collapse as the result of the weak physical characteristics of the material.

Of course, a variety of conventional writing instruments or pens is available, but such instruments are generally satisfactory only for writing on relatively porous surfaces. Such conventional marking instruments generally cannot be satisfactorily used for marking on relatively non-porous surfaces such as metal or glass.

It is an important object of the present invention to provide a novel marking element or tip element which is suitable for use in devices for marking or writing on many types of surfaces such as porous and non-porous surfaces.

A more specific object of the present invention is to provide a novel marking or tip element which may be used in marking devices of a type having fluid reservoirs with a body of absorbent material saturated with a marking fluid and which also may be used in connection with marking devices having open reservoirs filled with liquid ink such as in conventional fountain pens.

Still another object of the present invention is to provide a novel marking or writing element or tip which may be effectively used with marking fluids or inks comprising dyes or pigments dispersed in water and also with marking fluids or inks comprising dyes or pigments dispersed in organic solvents.

Another object of this invention is to provide a novel working element or tip for marking or writing devices of the above-described type and constructed for controlling and restricting the fiow of marking fluid so as to insure the laying down of a continuous uniform quality line or mark.

A further specific object of the present invention is to provide a novel marking element or tip of the above described type which may be selectively produced in a manner so as to write or mark with a relatively fine line or a relatively broad line and also in a manner so as to provide a fine line when held in one position and a relatively broad line when held in another position.

A still further object of the present invention is to provide a marking or writing instrument having a marking element or tip of the above described type which may be easily and economically produced and which is constructed so as to minimize any possibility of injury thereto.

A still further object of the present invention is to pro vide a novel method of producing marking elements or tips of the above described type in an efiicient and economical manner.

Other objects and advantages of the present invention will become apparent from the following description and the accompanying drawings, wherein:

FIG. 1 is a view showing a marking or writing instrument incorporating features of the present invention in position for marking or writing on a surface;

FIG. 2 is an enlarged partial vertical sectional view of the marking device in a position upside down from that shown in FIG. 1;

FIG. 3 is a further enlarged fragmentary sectional view similar to that shown in FIG. 2 and showing portions of the structure in greater detail;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is a perspective view showing a marking element or tip constructed in accordance with features of the present invention;

FIG. 6 shows a bundle of filaments or fibers from which marking elements or tips may be produced in accordance with features of the present invention;

FIG. 7 is a simplified view showing a portion of the method and apparatus for producing marking elements or tlps in accordance with features of the present invention;

FIG. 8 is a sectional view showing a marking element or tip in an intermediate stage of production;

FIG. 9 is a sectional view showing a further step in the finishing of the marking elements; and FICir. 10 shows a slightly modified form of the present invention.

Referring now more specifically to the drawings wherein l1ke parts are designated by the same numerals throughout the various figures, a marking device 10 incorporating features of the present invention is shown in FIGS. 1 through 5. The device 10 comprises a hollow body member or container member 12 providing a reservoir for marking fluid or ink, and a marking element or tip element 14.

The container or reservoir member 12 may be of a variety of known constructions. In the embodiment shown the container or reservoir member comprises upper and lower end portions 16 and 18 respectively formed from plastic or any other desired material. The upper and lower end portions are secured and sealed together as at 20. l

The continer or reservoir member 12 is substantially filled with a body 22 of fibrous or felt-like material or any suitable absorbent material which is adapted to be saturated with a liquid marking fluid or ink. However, it is to be understood that marking devices incorporating features of the present invention may be produced without utilizing the body 22 of absorbent material and the marklng fluid or ink may be placed directly in the open cavity defined by the container or reservoir member 12. Furthermore, the construction may be modified so that cartridges of ink constructed in a known manner and presently available may be placed within the container or reservoir member 12 as a substitute for the absorbent body 22.

In accordance with a feature of the present invention, the marking element or tip 14 comprises an elongated bundle or rod-like construction of a plurality of filaments or fibers 24. The filaments or fibers 24 extend generally axially of the element 14 and in many cases substantially parallel to each other and have a diameter such that small capillary-type passageways are defined between adjacent filaments of fibers and extend from an inner end 26 to an outer end 28 of the elemnet 14.

The size or diameter of the individual fibers or filaments in the bundle or rod-like member 14 may vary, for example, from the finest filament or fiber sizes utilized in known textile yarns to about 0.015 inch. It is contemplated that the optimum filament size may vary for different marking fluids or inks and, in general, the desired size or diameter of the filaments or fiber is that which will permit the marking fluid or ink to flow only by capillary action and at the same time will tend to prevent the capillary passageways 25 between the filaments or fibers from becoming blocked by the marking fluid or ink.

It is important to note that the filaments or fibers 24 are formed from a thermoplastic synthetic material. In general any thermoplastic material which may be formed as a filament or fiber of suitable size is adapted for use in marking elements of the present invention. However, it is recognized that the selection of the material for the filaments or fibers must in many cases be related to the type of marking fluid or ink which is to be used. In other words, the material of the filament or fiber must have a suitable resistance to swelling, softening or dissolving when exposed to the particular marking fluid or ink to be used. Plastic materials which are suitable for use in devices of the present invention and for use in connection with dispensing various marking fluids or inks include but are not limited to nylon, polyester, polypropylene, and cellulose acetate.

As indicated best in FIGS. 3 and 4, the fibers or filaments 24 providing a central core 27 of the element or tip 14 are separate from each other, although packed together, and define the aforementioned passageways 25 therebetween. It is to be noted, however, that the filaments or fibers at the peripheral surface of the marking element or tip 14 are bonded together to provide the element 14 with a substantially continuous imperforate peripheral film or shell 30. More specifically, the peripheral filments or fibers in the bundle are heated in a manher which will be described below and melted suificiently so that they flow together and adhere to each other to provide the shell. The shell provides strength and rigidity to the marking element or tip 14 so that it is self-supporting and, of course, serves to retain the central fibers in the core of the element 14. The thickness of the shell 30 may be varied by applying more or less heat to the bundle of fibers in the manner described below whereby the strength and rigidity of the element 14 may be varied and controlled and, in addition, the effective internal diameter of the element 14 may be controlled. In other words, the diameter of a central or core portion of the fibers 24 in which the capillary passageways 25 remain open may be varied as desired.

As shown in FIG. 3, the element 14 is formed at its outer end 28 so that the immediately adjacent portion of the shell 30 is upset or axially collapsed and radially expanded so as to provide a relatively strong and rigid enlargement 34 which in turn presents an axially inwardly facing shoulder 36. The rigid enlargement is capable of withstanding the pressures and wear occurring during a writing or marking operation. It should be further noted that the shell 30 is formed and extended at 35 so as to partially traverse the end of the central core portion 27 of the element 14, and the core fibers project slightly beyond the edge 35 for engagement with the writing surface. As shown in FIG. 3, the central opening at the end 28 defined by the anular edge 35 of the enlargement 34 has a diameter substantially less than the diameter of the core portion 27 throughout the remainder of the element 14. This construction promotes free and relatively rapid flow of the marking fluid or ink throughout the length of the element 14 and a dispensing of the fluid through the relatively narrow opening in a desired sharp or fine line. It will be appreciated that the width of the line in which the marking fluid is dispensed may be varied by changing the diameter of the opening at the end 28.

As shown in FIGS. 2 and 3, the element or tip 14 is mounted in a reduced diameter neck section 38 of the portion 16 of the reservoir member 12 so that the inner end 26 projects into the body of marking fluid or ink contained within the reservoir. In the particular embodiment shown, the inner end 26 projects into the absorbent material 22 which, as mentioned above, is adapted to be saturated with the marking fluid or ink.

The marking element or tip 14 is mounted within a reduced diameter neck section 38 of the reservoir portion 16 by means of a collar 50. As shown in FIG. 5, the collar is preferably axially slotted or otherwise vented as at 52. The marking element 14 fits within a central bore in the collar 50 with a force fit and the collar in turn is forced into the reduced diameter section 38 and retained therein by the force fit. Alternatively, the collar 50 may be formed integrally with the reduced diameter or neck portion 48 of the reservoir member if desired. The friction fit between the marking element 14 and the collar is usually sufficient to prevent the marking element from slipping axially outwardly. It is noted, however, that the aforementioned shoulder means 36 adjacent the outer end of the marking element or tip 14 is disposed for engagement with the outer end of the collar 50. This positive engagement between the elements prevents the marking element from being forced inwardly under the pressure applied thereto during a marking or writing operation.

A method of producing marking elements or tips 14 in accordance with features of the present invention is shown in FIGS. 6 through 9. More specifically, an elongated bundle of the fibers 24 in a relatively loose condition is provided as shown in FIG. 6 and preferably this bundle is provided as an elongated continuous strand 54 wound on a supply reel 56 as shown in FIG. 7. The strand 54 is drawn through one or more dies 58 and 60 by a pair of suitably driven rollers 62. Electrical heating means 63 connected with a suitable source of electrical energy is provided around the die 58. The dies 58 and 60 are formed with central apertures of predetermined diameters. Preferably the diameter of die 60 is slightly smaller than the diameter of die 58. Furthermore, the die 58 is heated by the heating means 63 to a temperature in excess of the temperature at which the material from which the strand 54 is formed will soften or melt sufliciently to provide the above described shell 30. Die 60 is maintained at a controlled temperature. While this temperature may be above room temperature, it is below the temperature at which the material from which the strand 54 is formed will soften or melt so that the die 60 functions to size the strand to the desired diameter. If necessary, Water or other cooling means 64 having water inlet and outlet tubes may be provided around die 60 to maintain the desired temperature. In certain installations one or more additional heated dies may be positioned between the die 58 and the sizing die 60. Thus, as the strand 54 is pulled through the dies 58 and 60 by the roller 62, the die 58 initially compacts the strand to a first predetermined diameter and heats the surface of the strand sufficiently so that the outermost fibers 24 at least partially melt and adhere together. As the strand passes through the second die 60, the fibers or filaments are further compacted together to provide the previously described capillary passageways 25 and the outermost melted strands from the aforementioned continuous and substantially imperforate shell 30 having the desired wall thickness.

The thickness of the shell wall depends on how much the strand 54 is heated and how far the heat penetrates toward the center of the strand sutficiently to soften or melt the fibers. Thus, the thickness of the shell wall may be increased by increasing the temperatures of the dies and/or slowing the speed at which the strand is drawn through the dies so that the heat will penetrate to a greater extent toward the center of the strand. Conversely, the thickness of the shell may be decreased by reducing the temperatures of the dies and/ or by drawing the strand through the die at a higher speed. In all events, however, care is taken to prevent adhesion of the innermost or core fibers to each other to an extent which will restrict the capillary action or the free flow of ink or marking fluid.

The compacted strand is cooled in passage through die 60 sufficiently to eliminate undue stickiness in the shell and is advanced from the driving rollers 62. The strand may be wound up on a supply reel, not shown, and subsequently severed into sections. Alternatively, the strand may be advanced directly from the drive rollers 62, as shown in FIG. 7, to severing means 66 from which severed elements 14 fall into a suitable receptacle 68.

The element 14 is in the condition shown in FIG. 8 as it leaves the severing means 66. In order to form the outer end of the element 14 so as to provide the reduced diameter opening at the end 28 and the enlargement 34 described above, the element is applied against the heated die 70 as shown in FIG. 9. More specifically, the element and the heated die 70 are relatively axially pressed together so that the die engages and melts ends of the strands spaced inwardly from the original shell 30 for reducing the opening or aperture at the end 28. At the same time, the configuration of the die and the tendency of the material to upset under the axially directed pres sure causes the shell 30 to be formed into the enlargement 34 previously described. The enlargement provides the tip with a rounded or ball-like or frusto-conical end which facilitates sliding of the tip over the surface on which the marking fluid is being dispensed during a marking or writing operation. The tip is formed so that the overall included angle between its diverging side surfaces is about 40 to 60. This forming of the tip prevents excessive melting either internally or at the extreme end and also strengthens it, and may increase the shell wall thickness at the tip if desired, and reduces any possibility of tip wear while at the same time the dimensions of the dispensing aperture 28 may be made as small as desired.

While the die 70 is shown as having a conical surface against which the element 14 is engaged for forming the element with a generally circular reduced diameter discharge aperture at the end 28, it is contemplated that the die may be modified so as to provide the element 14 with a non-circular discharge opening at the end 28. For example, the die 70 could be provided with a V-shaped surface so that the end of the tip when wedged between the opposite sides of the V would be provided with a relatively narrow slit-like discharge opening. FIG. 10 shows a modified element 14:: having such a construction. This element is substantially identical to the structure described above as indicated by the application of the same reference numerals with the sufiix a added to corresponding parts. The construction enables the instrument to be used for writing with a relatively fine line when held in one position so that the instrument is moved in a direction extending lengthwise of the slit. The instrument can also be used for writing with the relatively broad line when held in a position turned about 90 from the first mentioned position so that the instrument is moved in a direction generally transversely of the length of the slit.

While a preferred embodiment of the present invention has been shown and described herein, it is obvious that many details may be changed without departing from the spirit and scope of the appended claims.

The invention is claimed as follows:

1. A marking device comprising means providing a reservoir for marking fluid, and a marking element mounted in association with said means and presenting an exposed outer end and an inner end communicating with said reservoir, said marking element comprising an elongated bundle of elongated generally axially extending thermoplastic fibers, outermost fibers in said bundle being thermoplastically joined together and providing said bundle with an exterior irnperforate shell having substantially predetermined internal dimensions, innermost fibers in said bundle being substantially free of thermoplastic connection to each other and defining capillary passageways therebetween, said shell being substantially continuous and irnperforate for preventing the flow of fluid therethrough, and said shell including an integral outer end portion projecting transversely inwardly across ends of some of said innermost fibers and defining a relatively small fluid dispensing opening having transverse dimensions less than said predetermined internal dimensions.

2. A marking device, as defined in claim 1, wherein said shell includes integral upset and radially enlarged abutment surface means adjacent to and merging with said outer end portion thereof engageable with complementary means on said reservoir means for preventing said marking element from being forced inwardly.

3. A marking element for a marking device of the type described comprising an elongated bundle of elongated generally axially extending thermoplastic fibers, peripherally disposed fibers of said bundle being thermoplastically joined together and providing said bundle with an exterior shell having a predetermined internal dimension retaining innermost fibers in said bundle, said innermost fibers defining a plurality of capillary passageways therebetween, said shell being substantially continuous and imperforate for preventing the flow of marking fluid laterally therethrou'gh, and said shell including an integral outer end portion projecting transversely inwardly across ends of some of said innermost fibers and defining a relatively small fluid dispensing opening having a transverse dimension less than said predetermined internal dimensions.

4. A marking element, as defined in claim 3 wherein said opening has a generally circular configuration.

5. A marking element, as defined in claim 3 wherein said opening has .a generally elongated configuration.

6. A method of making a marking element of the type described comprising advancing a relatively loose bundle of elongated generally longitudinal extending thermoplastic fibers along a predetermined path of travel, heating and simultaneously compacting progressive portions of said bundle and causing peripherally disposed fibers in said bundle to soften and thermoplastically join together and thereby forming a substantially irnperforate shell around said bundle, subsequently cooling said shell, and applying heat and pressure generally axially to one end of said bundle and forming additional shell portions at said one end transversely inwardly for forming an opening at said one end of reduced dimensions and simultaneously upsetting and radially expanding an end portion of said shell substantially adjacent said additional shell portions for providing shoulder means engageable with means for mounting said marking element.

7. A method, as defined in claim 6, which includes the step of severing said bundle into increments of predetermined length.

References Cited UNITED STATES PATENTS 2,688,380 9/1954 MacI-Ienry 401198 X 2,870,471 1/1959 Albert 401202 2,891,272 6/1959 Wengeler 401-269 3,003,181 10/1961 Rosenthal 401-199 3,094,736 6/1963 Bunzl et al 401199 3,111,702 11/1963 Berger 401-199 3,190,294 6/1965 Dunlap 401198 X 3,203,025 8/1965 Schreur 401198 X LAWRENCE CHARLES, Primary Examiner 

